In recent years, as a result of widespread use of hybrid cars, electric cars and the like, large-current connector terminals are used in power supply lines and the like for supplying power to motors and the like. In connector terminals of this type to be fitted to each other to form a connector terminal pair, a Ag plating film having low contact resistance is generally used in an electric contact of the connector terminals.
For example, Patent Document 1 (JP2013-231228A) discloses a connector terminal including a base material made of Cu or a Cu alloy for forming a terminal, a Ag—Sn alloy plating film with which the surface of the base material is coated, and a Ag plating film with which the Ag—Sn alloy plating film is coated and that is exposed on the outermost surface.
In addition, Patent Document 2 (JP2011-74499A) discloses an electric contact including a composite plating film obtained by incorporating a certain amount of carbon particles into a Ag plating film.